1. Field of the Invention
The present invention relates to a deformation detecting agent composition that can easily detect sheet metal deformation (hereinafter deformation), especially deformation such as unevenness on the surface of a car body. It relates to a sheet metal deformation brightener composition that can easily detect deformation before surface treatment to permit correction so that efficient operation can be achieved due to a significant decrease in man-hours, and the factors of degradation in the corrosion resistance due to the deformation can be eliminated.
2. Description of the Prior Art
In pressed products such as sheet metal products manufactured by pressing, a deformation such as an unevenness, recess, protrusion, or distortion can be produced on their surfaces by inadvertent mishandlling. Such deformation on the surface of a product may cause serious problems in subsequent processes. For example, deformation in a sheet metal product will be noticeable after the product is coated in a subsequent process, so that a risk that the coated products cannot be used may arise. Therefore, these products must be subjected to an inspection process before the next manufacturing process.
In the inspection process, detecting deformation by scanning the surface of a product with a light beam and treating its reflected light has been proposed. In this case, if the surface of the product is not glossy or it has a remarkably low reflection efficiency, a surface suitable for the treatment cannot be obtained, and therefore the accuracy of the deformation detection may be reduced.
Then, a prior art that can solve the above problems has proposed preventing the diffuse reflection of light by coating the surface of a product with an oily liquid comprising a glossy oil (Publication of Japanese Unexamined Patent Application No. Hei 3-175000). Another prior art has proposed coating with a highly volatile liquid instead of the oily liquid so that the liquid does not remain in treatment in subsequent processes (Publication of Japanese Examined Patent Application No. Sho 48-7986).
In order to form a uniform glossy surface using the oily liquid comprising a glossy oil, it is preferable to use an electrostatic coating method, for example. However, the oily liquid is conductive, so that an insulation treatment is required for an electrostatic coating apparatus. Therefore, this method is very expensive. Highly volatile liquids such as alcohol and trichloroethylene are non-conductive, so that they do not require the insulation treatment. However, they are combustible and harmful, so that considerable care is required to use them.